A900
Vaccines
It is recommended that vaccines should be administered by a local
veterinarian. This is because veterinarians have access to superior vaccines
and can handle problems that may arise from vaccine reactions. The veterinarian
can also ensure that proper administration techniques are followed. However, if
individual situations require that the vaccine be given at home, the following
general suggestions are a must:
- Develop a vaccination schedule with the help of a veterinarian.
- Review and update the vaccination program annually.
- Refrigerate vaccines prior to use, and use entire contents after opening.
- Purchase all vaccines from a reputable source.
- Follow all label directions exactly.
- Give only the recommended dose by the recommended route.
- Use sterile syringes that have not been used for other purposes.
- Throw away all outdated and opened bottles.
- Do not use unnecessary vaccines.
- Do not mix two vaccines unless required by manufacturer.
- Do not vaccinate sick animals.
It is important that pet owners establish a consistent health program to
reduce the amount of infectious disease present on their premises. All
animals are susceptible to many infectious diseases. Infectious diseases can
enter a home/yard through new pets or be carried onto a location by other
animals and humans. It is important to identify what diseases are a potential
problem in the area or in the home. With a veterinarian, a strategy may be
formed for protecting against and decreasing exposure of a pet to infectious
diseases. A written vaccination schedule should be created and followed.
The vaccination schedule should be modified as conditions warrant and
available vaccines change. It is advisable to develop a complete program of nutrition, sanitation, and health care to help
ensure healthy and happy animals.
Terms:
- Vaccine: A vaccine is a mixture of killed or
modified microorganisms or their parts, administered to help prevent
sickness from infectious diseases.
- Adjuvant: A necessary component of inactivated
vaccines, adjuvants are additives to the vaccine suspension which help the
body’s immune system recognize the dead virus particles and mount an
effective immune response against them. Aluminum salts are usually the
adjuvant type seen in commercial veterinary vaccines.
- Active immunity: Active immunity is obtained
when the individual’s own immune system responds to an infectious disease.
The active immune response may be stimulated by either the disease itself or
a vaccine.
- Passive immunity: This type of immunity
against an infectious disease is obtained by receiving antibodies made by
another individual’s immune system. The most common example of passive
immunity occurs when a puppy consumes colostrum. Colostrum is the first milk
produced by the mother. It is rich in antibodies against diseases for which
the mother has immunity. When the puppy nurses from its mother for the first
time, it receives passive immunity against those diseases. Over time,
however, the maternal antibodies wear out, and the puppy must actively
mount its own immune response. Because of this decline in maternal
antibodies, it is essential to vaccinate puppies at a young age.
Modified Live
Vaccines:
Advantages
- One dose required
- Faster immune response
- Stronger and more durable response
- Fewer post vaccination reactions
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Disadvantages
- Not recommended for pregnant animals
- Possible viral shedding to other animals
- Improper handling may inactivate the vaccine
|
Killed Virus
Vaccines:
Advantages
- Usually safe for pregnant animals
- Stable in storage
|
Disadvantages
- Multiple doses required
- Weaker immune response
- Shorter duration of immune response
- Adjuvants may cause reactions
- Hypersensitivity reactions are more common
|
For a more detailed description
on vaccines, refer to the following information.
- Viral vaccines:
- Killed (inactivated) virus vaccines - These vaccines are composed of
whole or parts of the killed virus to which the body mounts an immune
response. Generally, killed virus vaccines are more stable for storage and
less likely to cause the disease being vaccinated against; however, they
are more likely to produce vaccination reactions due to the high level of
virus particles and the adjuvants that are used.
- Modified live virus vaccines (MLV vaccines) - These vaccines are composed of living viruses which have been altered to avoid causing the
disease being vaccinated against. Despite being changed, these vaccines
will still stimulate an immune response by the body. The changing process
(attenuation) of these viruses is usually accomplished through repeated
culturing of the virus in a tissue to which it is not adapted. Canine
distemper virus, for example, prefers to attack lymphoid cells in dogs. To
attenuate, or change its nature, CDV was cultured repeatedly through
canine kidney cells. The virus adapted to its new life, lost its ability
to cause disease (virulence), and can now be given as a vaccine to protect
against distemper in dogs. MLV vaccines do not require the use of
adjuvants, are less likely to produce vaccination reactions, and stimulate
a good immune response with fewer doses than a killed virus vaccine.
However, some MLV vaccines have been known to actually cause the disease
they are trying to prevent. This occurs when the attenuation or changing
process is not complete. Though rare, this has been known to happen with
canine distemper MLV vaccines and others to a lesser extent.
Conventional MLV vaccines vs. Potentiated MLV
vaccines - These terms refer to the modified live versions of parvovirus
vaccines currently available. Immunity against parvovirus is particularly
challenging to stimulate in puppies that nursed colostrum from their
mothers. This is because the passive immunity (from the mother) lasts for an
extended amount of time. For that reason, vaccine manufacturers have
recently started creating a parvo vaccine with a better ability to penetrate
passive immunity from the mother and stimulate an active immune response in
the puppy. These new parvo MLV vaccines are known as high titer or
potentiated vaccines. Low titer or conventional vaccines are still in use,
because they are very effective as boosters in adult dogs. The schedule for
parvovirus vaccination depends on the dog’s age, breed, access to
colostrum as a newborn, and type of vaccine being used.
Please see the vaccination schedule on page A905
for additional information.
- Bacterial vaccines:
- Bacterins - Bacterins are killed, whole bacteria or their parts. Some of
the bacterin vaccines are among the most notorious for producing vaccination
reactions. As with killed virus vaccines, bacterins are unlikely to cause
disease through retained virulence (ability to cause disease) and are more
stable for storage.
- Avirulent live bacteria (AVL) -
Bacteria can be made avirulent (non- infective) through different mechanisms.
Some of these mechanisms include gene manipulation and culture under abnormal
conditions. AVL vaccines are uncommon in veterinary medicine, although they do
exist for small animals, especially for intranasal use (i.e. Bordetella
vaccine).
- Fungal vaccines - No fungal vaccine has been approved for dogs, although
several show some promise for both prevention and treatment of certain fungal
diseases.
- Toxoids - This is an inactivated toxin (poison), administered to stimulate
the body’s immune response against the poison itself, rather than against the
organism which produces it. Probably most common is the tetanus toxoid. Due to
the delay in producing a response, toxoids are used in prevention rather than
treatment. Toxoids are also used because of their longer lasting effect.
- Antitoxin - An antitoxin is purified serum from another individual,
containing antibodies against a toxin. Antitoxins do not produce an immune
response and are not technically vaccines. They provide immediate protection
against a toxin and are given for treatment of existing disease, rather than for
long-lasting prevention. Antitoxins which are used in veterinary medicine
include tetanus antitoxin and rattlesnake venom antitoxin. Antitoxins are a form
of passive immunity.
- Antiserum - This is purified serum from another individual which contains
antibodies against different organisms (bacteria or viruses). Antiserum is
another form of passive immunity.
Note: The canine distemper, adenovirus,
parvo, and
parainfluenza vaccines
often come combined as one injection known as a "mixed" or
"cocktail" vaccine.